3D10.net is an online tabletop simulator that runs in your broswer in 3 glorious dimensions. Build units and unit sets to meet the needs of any game system and board game. Customize your table with textures and game boards. With support for 30+ unique units each with 30+ instances, there is plenty of room for epic dungeon encounters or galactic scale wargaming.
Something like 1200 units finally made me lag. Not bad considering my 5 year old hardware.